This invention relates to a process of preparing trifluoromethyltoluene from a relatively inexpensive compound, viz. a halomethylbenzotrifluoride.
Trifluoromethyltoluene (abbreviated to TFMT) is useful as an intermediate material for preparing medicines and argicultural chemicals.
According to FR No. 1,522,956, 4-TFMT is obtained by reacting 4-trifluoromethylbenzyl alcohol in acetic acid with hydrogen gas in the presence of PdO. However, the starting compound of this process is a very expensive material.
It is also possible to obtain TFMT by reacting a methylphenyl compound with a selected flouride. For example, reaction of 4-methylbenzoic acid with SF.sub.4 gives 4-TFMT. However, this reaction has to be carried out under high-temperatuare and high-pressure conditions, and SF.sub.4 is expensive and very toxic and is not readily available as an industrial material. Another laboratory process is reacting iodotoluene with CF.sub.3 I in the presence of CuSO.sub.4, but this method is not suited to industrial practice because of high price of CF.sub.3 I. Reaction of toluene with carbon tetrachloride and hydrogen fluoride also gives TFMT. All the reactants in this process are relatively inexpensive, but the product of this process is always a mixture of 2-TFMT, 3-TFMT and 4-TFMT (e.g., 13:42:45) difficult to separate and purify.